package com.atguigu.nio.groupchat;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;

/**
 * @author: 叶子
 * @date: 2022/01/22 11:10
 **/
public class GroupChatClient {
    //    定义相关的属性
    private final String HOST = "127.0.0.1";//服务器ip
    private final int PORT = 6667;//服务器端口
    private Selector selector;
    private SocketChannel socketChannel;
    private String username;
//    构造器 完成初始化工作

    public GroupChatClient() throws IOException {
        selector = Selector.open();
//         连接服务器
        socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));
//        设置非阻塞
        socketChannel.configureBlocking(false);
//        将channel 注册到selector
        socketChannel.register(selector, SelectionKey.OP_READ);
//        得到username
        username = socketChannel.getLocalAddress().toString().substring(1);
        System.out.println(username + " is ok……");
    }

    //    向服务器发送消息
    public void sendInfo(String info) {
        info = username + " 说：" + info;
        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    读取从服务器端回复的消息
    public void readInfo() {
        try {
            int readChannels = selector.select();
            if (readChannels > 0) {//有可以用的通道
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()) {
                    SelectionKey key = iterator.next();
                    if (key.isReadable()) {
//                        得到相关的通道
                        SocketChannel sc = (SocketChannel) key.channel();
//                        得到一个buffer
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
//                        读取
                        sc.read(buffer);
//                        把读到的缓冲区的数据转成字符串
                        String msg = new String(buffer.array());
                        System.out.println(msg.trim());
                    }
                }
                iterator.remove();//删除当前的selectionKey，防止重复操作，如果不写这一行，每个客户端只能读到其他客户端发送的一次数据
            } else {
//                System.out.println("没有可用的通道……");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {
//        启动客户端
        GroupChatClient chatClient = new GroupChatClient();
//        启动一个线程 每个3秒，读取从服务器端发送 的数据
        new Thread() {
            public void run() {

                while (true) {
                    chatClient.readInfo();
                    try {
                        Thread.currentThread().sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
//        发送数据给服务器端
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()) {
            String s = scanner.nextLine();
            chatClient.sendInfo(s);
        }
    }
}